How to unlearn habits?

I recently got into a healthy relationship after being in a heavily abusive one for 4 years, and I need some advice. Over my last relationship I often had to walk on eggshells and change my personality to keep my ex happy, and kinda just settled….into a pattern. For example, I’d have to apologize for not feeling well, or for making mistakes or even things as small as “acting off”, to name a few.

Today I told my new girlfriend I wasn’t feeling too well, and she was understanding and caring, which was very different than anything I’ve ever experienced.

I guess what I want to ask is….is it possible to unlearn old habits you used to have to apply for your abuser? I’m new to this whole situation, and I really don’t want my new girlfriend to feel I’m not being genuine cause of past traumas.